In fact, the American Jewish community is deeply split over the difficult policy challenge of confronting Iran’s nuclear program, with “hawks” and “doves” in the community engaged in heated, and at times acrimonious, exchanges.

On Wednesday, for example, in The New York Times, a full-page ad taken out by the liberal magazine Tikkun, the Network of Spiritual Progressives, and The Shalom Center was headlined in part: “No War on Iran and No First Strike.”

“We want to speak directly to the public as well as Congress and the president,” says Rabbi Arthur Waskow, leader of The Shalom Center in Philadelphia, in an interview. “We think there is a deep opposition to going to war; this is totally crazy this whole policy of a preemptive strike.”

The long-brewing crisis over Iran’s nuclear program seemed to become even more urgent over the weekend, as Republican presidential candidates addressed AIPAC's annual policy conference, with each one trying to sound more hawkish. Former Sen. Rick Santorum declared, for example, “If Iran doesn’t get rid of nuclear facilities, we will tear them down ourselves.”

President Obama likewise warned Iran to halt any effort to build a bomb. As the Shalom Center ad noted, the only difference between Obama and Israeli Prime Minister Benjamin Netanyahu seemed to be how long to use economic sanctions against Iran before resorting to military strikes. Obama did caution, however, that “Already there is too much loose talk of war.”

The issue of supporting Israel in the face of Iran’s nuclear aspirations is particularly sensitive for Obama as he seeks reelection. According to a September survey of American Jewish opinion conducted for the American Jewish Committee, 45 percent of Jews disapprove of the president’s handling of the Iran nuclear issue, while 43 percent approved.

But if sanctions and diplomacy – the preferred path so far for the Obama administration – fail, the survey found, some 56 percent said they supported military action against Iran to prevent it from developing a nuclear weapon; 68 percent supported Israel taking military action.

There are, nevertheless, many Jews who publicly disagree with the need for war, says Rabbi Waskow, whose supporters include Bianca Jagger, Jonathan Demme, the film maker, and Barry Commoner, an environmentalist who ran for president in 1980 under the Citizens Party ticket.

“There were so many people who signed and contributed we could not have printed all the names,” says Waskow. “It is important for people to know there are Jewish organizations and flesh and blood Jews who oppose the notion of a first strike against Iran.”

In the middle of this are many Jews who feel the issue has reached a sensitive moment and is delicately balanced. One of those is Rabbi Aryeh Feigenbaum of Congregation Ohr Ha Torah in Dallas.

“I would say that most of the Jewish community is not separate from the general community in that terms of being afraid of a nuclear Iran and also going to war,” he says in an interview. But, he thinks most Americans agree “a nuclear Iran is crossing the red line for the world. Israel would be the first to be attacked and we cannot let that happen.”

Last Saturday, Rabbi Feigenbaum told his congregation “the fear is real,” and it was time “to renew our prayers.”

The heated internal dispute in the American Jewish community started getting more attention in the media after March 1, when a group called the Emergency Committee for Israel ran a full-page ad in The New York Times attacking two liberal Washington-based think tanks, the Center for American Progress and Media Matters, for their views on the issue. Included in the ad were the names of phone numbers of key funders for both organizations.

The Emergency Committee ad was particularly critical of Jewish columnist M.J. Rosenberg of Media Matters, who used the term “Israel-Firster” to refer to those American Jews who want to go to war to prevent Iran from developing a nuclear bomb.

“Israel Firster has a nasty anti-Semitic pedigree,” wrote Alan Dershowitz, the noted lawyer and Harvard professor, who vowed to get Mr. Rosenberg fired from Media Matters.

Mr. Rosenberg, who was not available to comment, still works for Media Matters.

Noah Pollak, executive director of the Emergency Committee, says in an email that the Center for American Progress has “conceded the phrase ‘Israel-Firster’ is anti-Semitic" and “claims to have taken steps to deal with inappropriate rhetoric by their staffers – though we do not believe they’ve done enough.”

He says the phrase implies that pro-Israel Jews are not loyal and patriotic Americans. “Media Matters has done nothing to address the problem,” he writes.

For its part, Media Matters says it is an organization dedicated to accuracy and fairness in news coverage. “We have a long track record of holding those who hold anti-Semitic views accountable,” says Ari Rabin-Havt, executive vice president of Media Matters. “The kind of claim made in the ad is ridiculous.”

In a column in the Huffington Post, Mr. Rosenberg said his comments really were about those who support Mr. Netanyahu. “The people I call ‘Israel Firsters’ are, in fact, Netanyahu Firsters,” he wrote.

"After all, if they were putting Israel first, they would not be promoting policies (such as war with Iran or the perpetuation of the occupation) that could very easily lead to Israel's destruction or, at least, to its losing its Jewish majority.”